Ch.49 Chemical Signals In Animals

**Which of the following experiments would help in the identification of a suspected hormone?

Injection of source gland extract into an animal that lacks the source gland

**In what ways are the chemical classes of hormones similar to or different from one another?

Some amino-acid-derived hormones are lipid soluble; most are water soluble.

**Which of the following statements accurately characterizes a chemical that could be a functioning hormone?

The chemical is present at low levels in the bloodstream yet causes great physical responses.

**Which of the following statements accurately describes hormone receptors?

Steroid hormones bind to receptors located inside target cells.

**Endocrine glands differ from exocrine glands in that they are known to _____.

release hormones into the bloodstream for distribution around the body

**Hormones coordinate the activities of cells in response to three situations:

- development, reproduction, and growth

- enviornmental challenges

- homeostasis

**Which of these situations might lead to the adrenal glands releasing epinephrine but NOT cortisol?

Witnessing a car accident

**Which of the following statements accurately describes the actions of the indicated hormone?

Aldosterone produced by the adrenal glands controls the reabsorption of sodium ions by the kidneys.

**Mice that are homozygous for obese (ob/ob) or diabetic (db/db) gene products eat much more food and move much less than normal mice. To determine the function of these gene products, researchers used a technique called parabiosis, in which two closely related animals are surgically united to allow the passage of long-lived molecules. What conclusions were drawn from this experiment?

The gene products obese and diabetic are involved in hormonal signaling that affects appetite and activity level.

**Which of the following statements best illustrates the concept of feedback inhibition within the endocrine system?

An increase in cortisol released by the adrenal glands causes a decrease in CRH released by the hypothalamus.

**Predict the effects of administering ACTH to a rat a few days after it has had its pituitary gland removed.

The adrenal glands will grow in size.

**Metamorphosis in amphibians is controlled by which hormone pathway?

The anterior pituitary releases thyroid-stimulating hormone (TSH), which stimulates the thyroid to produce thyroxine (T4) that is converted to T3 at the target tissues.

**What is one similarity that links the endocrine system and nervous system?

The release of one type of signal, chemical or electrical, is regulated by the release of the other type of signal.

**Studies on the estradiol receptor determined which of the following to be a characteristic of the receptor?

The estradiol receptor is a protein.

**Which of the following statements provides the best definition of a hormone-response element?

A hormone-response element is a DNA sequence that binds a specific hormone-receptor complex.

**What is the significance of the discovery of different receptor types for the hormone epinephrine?

Different tissues responded differently to the presence of epinephrine.

**Which molecule serves as a second messenger for epinephrine's actions on glucose production?

cAMP

**What is the correct sequence of events following the binding of epinephrine to a liver cell?